The aim of this proposal is to develop an effective and rapid method for disrupting the poultry-to-human transmission of avian influenza by in ovo injection of adenovirus-vectored avian influenza vaccines that can be mass-produced in cultured cells and mass-administered with a mechanized injector. The hypothesis is that mass-vaccination of poultry against an outbreak of avian influenza reduces the dissemination of the virus to new flocks and consequently the risk to humans. As avian influenza gets more and more deadly, it is increasingly urgent to produce vaccines rapidly in response to an unprecedented escalation in demand. We have demonstrated that chickens can be immunized against highly pathogenic avian influenza viruses by in ovo administration of non-replicating adenovirus vectors encoding an avian influenza virus hemagglutinin. In contrast to conventional avian influenza vaccines, this new class of avian influenza vaccine does not mask natural infections by an avian influenza virus. The recombinant adenovirus vector can be rapidly generated using Vaxin's proprietary AdHigh system without the requirement to propagate lethal avian influenza viruses. The Phase II studies will further explore the potential of an adenovirus-vectored in ovo vaccine in mobilizing the immune repertoire toward a beneficial immune protection against avian influenza in chickens. In this project, the potential for an adenovirus-vectored in ovo avian influenza vaccine to immunize breeder hens and progeny chickens will be investigated; the fate of adenovirus vectors in chickens following in ovo administration will be determined; vaccination of chickens against multiple avian diseases by adenovirus-vectored in ovo vaccines will be developed; the compatibility between an adenovirus-vectored in ovo vaccine and the DIVA strategy for immunization of poultry will be defined; and the potency of adenovirus-vectored in ovo vaccines under field conditions will be analyzed. The overall goal of these experiments is to develop a new generation of avian influenza vaccine that can be rapidly manufactured and administered for mass-immunization of poultry in response to a crisis. PUBLIC HEALTH RELEVANCE: Avian influenza represents a major impending threat to public health. Mass-vaccination of poultry flocks against this deadly disease will be a crucial tool for reducing the rapid spread of the anticipated human pandemic. Vaccinating eggs before they hatch is much faster, easier, and less expensive than vaccinating live birds. The aim of this proposal is to develop a safe and effective vaccine which can rapidly vaccinate eggs to stop or slow the spread of the avian influenza, thus protecting humans as well as a significant food source. A genetically modified adenovirus is the basis of this new type of vaccine. [unreadable] [unreadable] [unreadable]